The present invention is with respect to a transport unit for castings, covered to a greater or lesser degree with foundry sand, for use in a foundry conveying plant and with a casting supporter for use with the transport unit as part of a blasting apparatus, for the purpose of supporting the castings while they are in the process of being cleaned. The supporter is designed for turning the castings about a generally level axis and furthermore transporting them.
The design of conveying and handling systems in a foundry necessarily has to be complex, because the material to be transported comes in a large number of different forms and different compositions. For example after teeming, the mold flask--or in the case of flaskless systems the foundry sand casing--has to be moved along a cooling path, whereafter the casting or castings are freed as completely as possible of their sand in a shakeout, that may for example have a vibrating screen. Next the castings, that, as noted, may be in a number of widely different forms as for example small flanges or, at the other end of the scale, heavy and complex engine cylinder blocks, are moved into and through a blasting unit, in which, if necessary, they may be turned about their own axes, before they are handed over to a further conveying system for moving them on further to a different processing unit, for example for taking off flash. The different form and nature of the castings make it necessary to have different sorts of conveying mechanisms, of a more or less complex design, along the transport path in question.
A suggestion has been made in the past (see German Offenlegungsschrift specification No. 2,631,385) to have an overhead conveyor running right along this transport path with hanging baskets as transport units for the sand casings with the castings inside them so that at the shakeout station the sand may be cleared from the castings and the castings kept within the baskets for further transport through the blasting cabinet. Because of the basket design it is on the one hand possible for the foundry sand to be cleared from the castings without any trouble in the shakeout, while on the other hand the cleaning jet may readily get to all parts of the castings, the loose sand then falling down from the castings without anything in its way. While it is true that such a design is very much simpler with respect to the conveying apparatus needed, it is of little use in some cases because the castings in the blasting cabinets are not changed in position in relation to (for example by being turned over) the cleaning jets so that, more specially in the case of castings with complex forms and spaces opening in different directions, some core sand may well be kept back in such openings.
On the other hand blasting cabinets are known (see German Auslegeschrift specification Nos. 2,510,827 and 2,613,717) in which the castings, more specially heavy and complex ones such as cylinder blocks and the like, are taken up by a special supporter and transported thereby through the blasting cabinet, the supporter being made up, generally speaking, only of rods, by way of which the castings are supported at a limited number of points so that the casting is not covered up and may be freely acted upon all over by the blasting jet. These supporters for the castings have a drive by which they are kept turning about a roughly horizontal axis so that all points on the casting are acted upon by the cleaning jet, the loosened sand then freely falling out of pockets and holes in the castings. In the one case (see German Auslegeschrift specification No. 2,510,827) the supporter for the castings is in the form of a horizontal tongs, whose jaws are formed by a fixed rod and two rocking rods joined together by a cross-rod. In the other case (see German Auslegeschrift specification No. 2,613,717) the supporter is in the form of a generally horizontal basket cage with a wall across it so that one part thereof may be folded open and shut again, so as to give a further tongs-like mechanism. In such tongs-like supporters the castings are moved along a straight or curved path through the blasting cabinet and at the same time are turned over by a turning drive. This known system does however have the shortcoming again that the conveying systems may not be made uniform or standardized and that the castings each have to be handed over from one part of the plant to another a number of times.